DETROIT, MI -- Just after a group of immigrants' rights activists picketed outside the Rosa Parks Federal Building, an Immigration and Customs Enforcement official said Everilda Calvo-Sanchez, an unauthorized immigrant detained on April 2, was released Thursday afternoon.

The protesters highlighted Calvo-Sanchez and several other detainees they said were being aggressively prosecuted against federal policies that call for discretion under certain cases.

"Everilda Calvo-Sanchez was released from ICE custody today," said ICE spokesman Khaalid Walls. "As an exercise of discretion, ICE granted a one-year stay of removal after reviewing all factors of the case."

Calvo-Sanchez, who moved to the U.S. in 1998 from Guatemala, was arrested in the Grand Rapids area last week when police pulled over an unlicensed driver with whom she was riding as a passenger. Activists said her sister and nephew were killed by a criminal organization in Guatemala and that she should qualify for asylum.

They called for the release of several other recent detainees being held at the Calhoun County Jail and criticized ICE operations in Michigan under field director Rebecca Adducci.

Walls in response said ICE is focusing on removing immigrants who pose threats to public safety.

"Through smart and effective immigration enforcement, ICE is committed to ensuring that its limited resources are focused on the removal of those who pose a threat to public safety such as criminal aliens and national security threats, as well as repeat immigration law violators, recent border entrants, and fugitives from immigration court," he said in an email message.

"Michigan ICE specifically is very, very aggressive," said activist Mohammad Abdollah of Ann Arbor, an unauthorized immigrant who was brought to the U.S. at age 3.

"There's this track record of very aggressive prosecution that I think is somewhat unique... We hear stories of these families and it's traumatic."

Gustavo Corona was detained April 1 after being pulled over by Ypsilanti police while driving without a license, according to activists.

Santiago Garcia, an activist and unauthorized immigrant who traveled to Michigan from North Carolina to protest, said Corona qualifies for the federal governments recently implemented Deferred Action for Childhood Arrivals program, which allows young immigrants to apply for work visas.

He said Corona's wife and two ill daughters are devastated by the detainment.

"The children are the ones that are most affected," Garcia said. "It's really stressful for them right now."

ICE officials couldn't immediately find records on Corona's case.

Activists also called for the release of detainee Maria de la Luz Mendoza-Martinez, who they said has been bleeding while in custody due to untreated cysts in her ovaries.

Walls said Mendoza-Martinez was convicted on federal counterfeit document charges last year and was turned over to ICE after serving her sentence.

"She will remain in custody pending the outcome of removal proceedings against her," he said.

The Detroit protest came as Congress debates various immigration policies and activists nationwide, thousands of whom marched in coordinated rallies Wednesday, push for comprehensive reform.